INSTALLATION & SERVICING MANUAL BENSON PV TUBULAR CABINET HEATER

Technical Support: 

Tel: 01384 489200 

Email: ambiradgroupsupport@tnb.com 

INSTALLATION & SERVICING MANUAL FOR 

BENSON PV TUBULAR CABINET HEATER 

NATURAL GAS (G20 I 2 H), PROPANE GAS (G31 I 3 P) 

WARNINGS 

Benson equipment must be installed and maintained in accordance with the relevant 

provisions of the Gas Safety (Installations and Use) Regulations 1998 for gas fired products. 

Due account should also be taken of any obligations arising from the Health and Safety at 

Works Act 1974 or relevant codes of practice. In addition the installation must be carried out 

in accordance with the current IEE wiring regulations (BS 7671), BS 6896 (Industrial & 

Commercial) and any other relevant British Standards and Codes of Practice by a qualified 

installer. All external wiring MUST comply with the current IEE wiring regulations. 

1 

AmbiRad Limited, Fens Pool Avenue, Brierley Hill, West Midlands, DY5 1QA

Section Contents Page No 

1.0 Compliance Notices 4 

1.1 Certificates of Conformity 5 

1.2 General product Information 5 

1.3 General Requirements 6 

1.4 Delivery & Pre-installation Checks 6 

1.5 Warranty 7 

1.6 Special risk areas 7 

2.0 Installation 8 

2.1 Installation Clearances 8 

2.2 Warm Air Circulation 8 

2.3 Air Supply 8 

2.4 Flue Installation 13 

2.5 Electrical Installation 18 

2.6 Gas Installation 20 

3.0 Commissioning 20 

3.1 Electrical Pre tests 21 

3.2 Gas supply Pre tests 21 

3.3 Ignition Sequence 21 

3.4 Hand Over 22 

4.0 Servicing 23 

4.1 Servicing Procedure 23 

5.0 Fault Diagnosis 26 

6.0 Wiring Diagrams 28 

7.0 Technical Data 43 

7.1 Technical Data Common Information 43 

7.2 Technical Data Heater Specifications 44 

8.0 Parts Listing 45 

9.0 All Dimensions 46 

2

WARNING 

ELECTRICAL INSTALLATION 

When installing the heaters and using the remote controls option 

ALL 8 WIRES MUST BE USED AT ALL TIMES . 

IMPORTANT NOTICE TO INSTALLERS 

Installers should satisfy themselves that the gas pipework installation is carried 

out in accordance with all current legislation, Codes of Practice and 

Recommendations. 

Additionally it may be necessary to protect the gas valves which form part of 

the heater or burner assembly from potential pipe contamination particularly, 

but not exclusively , where copper gas pipework is used. 

In instances where copper pipework is to be used for all or part of a gas 

pipework installation, including short length final connections then we advise 

that installers consult with gas supplier or provider and satisfy themselves what 

additional precautions may be necessary 

Any reference made to Laws, Standards, Directives , Codes of Practice or other 

recommendations governing the application and installation of heating appliances and 

which may be referred to in Brochures, Specifications, Quotations, and Installation, 

Operation and Maintenance manuals is done so for information and guidance 

purposes only and should only be considered valid at the time of the publication. 

Benson Heating cannot be held responsible from any matters arising from the revision 

to or introduction of new Laws, Standards, Directives, Codes of Practice or other 

recommendations. 

3

1.0 Compliance notices 

The Benson PV Range of warm air heaters 

detailed herewith are manufactured for 

Benson Heating within a strictly controlled 

environment within the parameters of 

ISO9001. 

These instructions are only valid if the 

following country code is on the appliance 

GB. IE. If this code is not present on the 

appliance, it is necessary to refer to the 

technical instructions which will provide the 

necessary information concerning the 

modification of then appliance to the 

conditions of use for the country. 

The Benson PV Range has been 

independently tested and assessed, and 

has been found to meet the Essential 

Requirements of the following European 

Directives. 

Gas Appliance Directive (90 / 396 / EEC) 

Machinery Directive (2006 / 42 EC) 

Low Voltage Directive (2006 / 95 / EC) 

Electromagnetic Compatibility Directive 

(2004 / 108 / EC) 

Product Liability Directive (85 / 374 / EEC) 

The manufacturer has taken reasonable and 

practical steps to ensure that Benson PV 

Range of Heaters are safe and without risk 

when properly used. These heaters should 

therefore only be used in the manner and 

purpose for which they were intended, and 

in accordance with the recommendations 

detailed herewith. 

The heaters have been designed, 

manufactured, assembled, inspected, and 

tested, with safety and quality in mind, there 

are certain basic precautions which the 

installer and user should be aware of, and 

they are strongly advised to read the 

appropriate sections of the information pack 

accompanying the heater, prior to 

installation or use. 

Benson Heating supports all new products 

being supplied to their customers with a 

comprehensive information pack; this clearly 

defines mandatory instructions for the safe 

installation, use, and maintenance, of the 

appliance (s). 

Where proprietary items are incorporated 

into Benson products, detailed information 

and instructions are also provided as part of 

the information pack. 

It is the responsibility of the installer, owner, 

user, or hirer, of such products supplied by 

Benson Heating, to ensure that they are 

familiar with the appropriate information/ 

manuals, supplied by the manufacturer, and 

that they are suitably aware of the purpose 

of the manuals and the safety instructions. 

In addition, operators must be suitably 

trained in the use of the appliance so as to 

ensure its continued safe and efficient use. 

Benson has a commitment to continuous 

improvement, and therefore reserves the 

right to amend or change the specification of 

the PV Heater Range subject to agreement 

from The Notified Body. 

Contained within the text of the manual, the 

words 'Caution' and 'Warning' are used to 

highlight certain points. 

Caution is used when failure to follow or 

implement the instruction (s) can lead to 

premature failure or damage to the heater or 

its component parts. 

Warning is used when failure to heed or 

implement the instruction (s) can lead to not 

only component damage, but also to a 

hazardous situation being created where 

there is a risk of personal injury. 

The Benson PV Range of heaters conform 

to the following European Harmonised 

Standards. 

BS EN 1020 Requirements for non domestic 

gas fired forced convection air heaters for 

space heating incorporating a fan to assist 

transportation of combustion air and/ or 

combustion products. 

BS EN - ISO 12100-1 

& BS EN - ISO12100-2 

Safety of Machinery - Basic Concepts, 

General Principles for Design 

Part 1 & Part 2 

4

BS EN 60204 - Part 1 

Safety of Machinery - Electrical Equipment 

for Machines Specification for General 

Requirements 

BS EN 60335 - Part 1 

Safety of Household and Similar Electrical 

Appliances General Requirements 

BS EN 55014 

Limits and methods of measurement of 

radio disturbance characteristics of electrical 

motor-operated and thermal appliances for 

household and similar purposes, electrical 

tools and similar electric apparatus 

BS EN 50165 

Electrical Equipment of non-electric heating 

appliances for household and similar 

purposes, safety requirements 

The Benson PV range of gas unit heaters 

meet with the governments criteria in 

respect of the Enhanced Capital Allowance 

Scheme 

1.1 Certificates of conformity 

Declarations and Certificates are available 

upon request from the Quality Control 

Department at Benson Heating. 

1.2 General product information 

The Benson PV Range of 6 model sizes 

have outputs from 29.4 kW to 144.0 kW, 

PV heaters are suitable for operation on 

Natural gas (G20) or LPG (Propane G31) 

The Model Range is made up as follows and 

are available in a configuration that will allow 

for floor mounting only. 

Model No 30 50 72 

Output kW 29.4 49.0 72.0 

Model No 95 120 145 

Output kW 96.0 120.0 144.0 

PV heaters have been approved for 

alternative flue discharge arrangements but 

each heater must be connected to its own 

individual open flue these are detailed in 

following page’s 

Cabinet 

Manufactured from electro-zinc coated steel, 

finished in a durable stove enamelled 

polyester powder paint. 

Heat Exchanger 

Manufactured from aluminised dimpled steel 

tube formed into a W shape to give 

enhanced efficiency . 

Flue / Combustion Air Spigot 

Each heater is fitted with two spigots both of 

which are located on top of the appliance. 

One of the pair is for connection for the flue 

whilst the other is a screened combustion air 

intake SEE SECTION 2.4 FLUE 

INSTALLATION 

Burner 

The induced draught multi in-shot burner 

assembly is manufactured from aluzinc 

coated steel and mounted to a common 

steel manifold which can be easily 

withdrawn through the burner access 

compartment. 

Burner Control 

The heaters are fitted with automatic 

ignition for all models within the range. 

Exhaust Fan 

Combustion gases are evacuated to 

atmosphere via an in built power flue venter 

fan which is safety interlocked to the gas 

valve via an air pressure proving device 

Air Movement Fan 

PV heaters are supplied with Centrifugal 

fans suitable for ducted or free blowing 

applications 

Note 

Neither asbestos nor soft soldered joints are 

used in the construction or manufacture of 

the Benson Heating range of Heaters. 

5

The materials selected for use can 

withstand the mechanical, chemical, and 

thermal stresses which they will be subject 

to during foreseen normal use when 

installed in accordance with the 

manufacturers recommendations. 

1.3 General Requirements 

Caution 

Before installation, check that the local 

distribution conditions, nature of gas and 

pressure, and the current state adjustment 

of the appliance are compatible. 

Warning 

Unauthorised modifications to the appliance, 

or departure from the manufacturers 

guidance on intended use, or, installation 

contrary to the manufacturers 

recommendations may constitute a hazard. 

Note 

To ignore the warning and caution notices, 

and to ignore the advice from the 

manufacturer on installation, commissioning, 

servicing, or use, will jeopardise any 

applicable warranty, moreover, such a 

situation could also compromise the safe 

and efficient running of the appliance itself, 

and thereby constitute a hazard. 

This appliance must be installed by a 

competent person and in accordance with 

European, National, and Local criteria, 

including any relevant standards, codes of 

practice the requirements of the current 

building Regulations (and in particular parts 

J & L), Health and safety regulations IEE 

regulations and any requirements of the 

Local Authority, Fire Officer or insurers. 

Relevant standards may include BS6230, 

BS6891 and BS5588 parts 2 and 3 

Prior to installation the following points 

should be considered; 

a) The position of the heater for the 

optimum efficient distribution and circulation 

of warm air. 

b) The position of the heater relative to the 

route of the flue. 

c) The position of the heater relative to the 

supply of gas. 

d) The position of the heater relative to the 

electrical services, wiring routes, and if 

appropriate, any additional controls. 

e) The position of the heater relative to the 

supply of fresh air. 

f) The position of the heater relative to 

potential stratification / circulation problems, 

which generally occur at higher levels and 

which may be overcome through the 

provision of a suitable de-stratification unit. 

g) The position of the heater relative to 

service and maintenance requirements. 

Caution 

The heater must not be installed within an 

area where the conditions are unsuitable, 

e.g. where the atmosphere is highly 

corrosive, has a high degree of salinity, or 

where high wind velocities may affect burner 

operation. Suitable protection should be 

provided for the appliance when it is located 

in a position where it may be susceptible to 

external mechanical damage from; for 

example, fork lift trucks, overhead cranes 

etc. 

1.4 Delivery and pre-installation 

checks 

The heater is supplied wrapped in heavy 

duty protective polythene, mounted on a 

pallet. 

On receipt of the heater, the following 

checks should be carried out; 

a) The model is as per order. 

b) That it is undamaged. 

c) That it is suitable for the gas supply and 

pressure. 

d) That it is suitable for the electrical supply. 

If any of these points are not satisfied then 

contact should be made with the Sales 

Office at Benson Heating as soon as 

possible by telephoning 01384 489200. In 

the case of claims for damage, this must be 

reported in writing within 24 hours of 

delivery, in order to comply with insurance 

criteria 

6

1.5 Warranty 

The heater is supplied with a 1 year parts 

and labour warranty and a further year on all 

parts excluding consumable’ s. 

In addition to this there is also a 10 year 

time related warranty on the combustion 

chamber. 

The warranty commences from the date of 

dispatch from the manufacturer, and is 

subject to the terms detailed within the 

Benson Heating 'conditions of business'. 

Note (i) 

The warranty may be invalidated if - 

a) The installation is not in accordance with 

the general requirements of this manual. 

b) The flue arrangement and air supply for 

the heater are not in accordance with the 

manufacturers recommendations, codes of 

practice, or similar standards. 

c) Air flow through the heater is not in 

accordance with the manufacturers 

technical specifications. 

d) Internal wiring on the heater has been 

tampered with or unauthorised service / 

repairs undertaken. 

e) The main electrical supply input to the 

heater has been interrupted during the 

heating mode. 

f) The heater has been subject to and 

affected by the ingress of water in any form. 

h) The heater is not operated at the rating(s) 

laid down in the manufacturers technical 

specifications. 

g) The heater has not been operated or 

used within the normal scope of its intended 

application. 

h) The manufacturer's recommended 

minimum service requirements have not 

been complied with. 

Note (ii) 

All warranty claims must contain the 

following information to enable processing to 

take place; 

(1) Heater model 

(2) Heater serial number 

(3) Order reference/date of order, together 

with full installation details (name and 

address) 

(4) Details or symptoms of fault 

(5) Installers name and address. 

Faulty parts must be returned to the Benson 

heating Spares Department, the address of 

which is provided on the rear cover of this 

manual. Any such parts will undergo 

inspection to verify the claim. Replacement 

parts supplied prior to this may be charged, 

and a credit supplied upon subsequent 

validation of the warranty claim. 

Consumable items are specifically not 

included within the scope of the warranty. 

Note (iii) 

Notification is required immediately a fault is 

suspected. 

The manufacturer will not accept 

responsibility for any additional damage that 

has been caused, expense incurred, or 

consequential loss resulting from any failure 

of the heater(s). 

1.6 SPECIAL RISK AREAS 

Where it is proposed to install a heater 

within a special risk area (e.g. an area 

containing flammable vapours where petrol 

engined vehicles are stored parked or 

serviced where paint spraying occurs, or 

where woodworking machinery or other 

flammable dust creating process’s are 

employed then restrictions, additional 

regulations concerning the heater flue wiring 

or controls may apply. 

It is strongly recommended that you contact 

Benson Technical before installation. 

Caution 

When used in room sealed mode it may be 

possible to install PV heaters in areas 

containing flammable vapours, high levels of 

airborne dust combustible dust chlorinated 

or halogenated hydrocarbons degreasing 

solvents styrenes other laminating materials 

or airborne silicones. Benson Technical 

should be contacted before installation. 

7

Failure to do so may invalidate or reduce 

guarantee cover. 

Plant Room Siting 

Provided certain criteria are met it is 

possible to install PV heaters within a plant 

room heaters installed in plant rooms should 

only be configured for use in room sealed 

mode and provision should be made for the 

positive connection of flues , combustion air 

pipes, warm air discharge and return 

ductwork where such a siting is a 

requirement it is recommended that you 

consult Benson Technical prior to 

installation. 

Additionally the maximum temperature 

within the plant room should not exceed 

32 0 C 

etc) it is considered favourable if the heater 

is positioned so as the discharge towards or 

across the cold air source from a distance 

from 1.5m - 6m dependent upon the size of 

the entrance and the air throw 

characteristics of the heater. On exposed 

walls heaters should be positioned so as to 

discharge towards, or along the length of the 

exposed wall. 

In areas where it is proposed that more than 

one heater is to be installed, a general 

scheme of circulation should be drawn up 

and maintained, thereby offering the best 

heat distribution. Air pressure within the 

area heated and the outside air pressure 

must remain the same, factors influencing 

this would be the presence of extraction 

systems, ventilation systems, and various 

types of process plant. 

2.0 Installation 

The location chosen for the heater must 

allow for the fitting of an effective flue 

system. 

The location must also allow for adequate 

clearance for the air supply, return air 

circulation, gas supply, electrical supply, 

whilst also providing good and safe working 

access. 

The heater must be installed on a flat and 

level surface made from non-combustible 

material, which is sufficiently robust to 

withstand the weight of the heater and any 

ancillary equipment. 

Any combustible material adjacent to the 

heater or flue system must be so placed or 

shielded so that its surface temperature 

does not exceed 65 0 C. 

PV free blowing heaters are at their most 

effective when located as close to the 

working area as possible. However care 

should be exercised to avoid directing the 

discharged air directly onto the occupants of 

the area to be heated. 

Where the passage of cold air causes 

problems (e.g. by entrances, loading bays 

2.1 Installation Clearances 

The Heater must be installed within the 

clearances indicated below in mm’s 

Model Front Rear Lhs Rhs 

30/50 700 400 150 150 

72/95 840 400 150 150 

120/145 840 400 150 150 

2.2 Warm Air Circulation 

The air heater should be positioned to 

enable maximum circulation of discharged 

warm air within the area to be heated, whilst 

taking account of personnel within the area, 

sources of cold air ingress, and 

obstructions. 

The air temperature rise on passing the heat 

exchanger is typically around 33 0 C 

A full and unobstructed return air path to the 

air heater must be provided 

(see 2.4 Air Supply). 

Where the heater is positioned to deliver 

blown air through an opening in a wall, 

return air intakes should be located so that 

8

they cannot become blocked. Similarly 

these intakes must be positioned so as not 

to draw in odours, fumes, hazardous 

vapours or particles. 

2.3 Air Supply for Combustion and 

Ventilation 

Consideration must be given to the provision 

of air for the purposes of combustion and 

ventilation of the heated space, plant room 

or enclosure where the heaters are to be 

installed . 

It is strongly recommended that BS 6230 is 

referred to for further information concerning 

ventilation requirements. 

2.3.1 Heaters installed within the 

heated space 

Where heaters are installed within the 

heated space (i.e. not a plant room , or 

enclosure) then: 

Combustion air or heater related ventilation 

air will not be required if - 

The heaters are installed in room 

sealed mode (ie with a positive 

connection to atmosphere of both flue 

and combustion air) 

OR 

 

If the design air change rate of the 

heated space is 0.5 air changes per 

hour or greater 

The design air change rate may be satisfied 

by natural infiltration or by mechanical 

ventilation. 

Combustion air ventilation will be required if 

The heater(s) are installed with flue 

only (ie without the positive connection 

to atmosphere of a combustion air 

duct) 

And 

 

The design air change rate of the 

heated space is less than 0.5 air 

changes per hour. 

Where heater(s) are installed without the 

positive connection of combustion ductwork 

within a heated space where air change rate 

of that heated space is less than 0.5 air 

changes per hour then it will be necessary 

to provide either natural ventilation openings 

to the heated space (Section2.3.1.1 refers) 

or the mechanical ventilation of the heated 

space (Section2.3.1.2 refers). 

2.3.1.1 Natural Ventilation Openings 

to the Heated Space 

If the heater(s) are to be installed without 

the positive connection of combustion air 

ductwork within a heated space, and where 

the design air change rate of that heated 

space is less than 0.5 air changes per hour, 

then provision for low level natural 

ventilation openings only will be necessary. 

The minimum free area of the low level 

natural ventilation opening shall be 

 

2 cm 2 for each kW of rated heat input 

The low level natural ventilation opening 

should be situated on an external wall and 

be within 1000 mm of floor level for natural 

gas and ideally at floor level for lpg gas 

installations but in any event no higher than 

250 mm. 

The table below provides specific data for 

each heater model as - 

MODEL 

Minimum Free Area Of 

Ventilation Opening 

High Level 

Low Level 

cm 2 cm 2 

30 None 64 

50 None 107 

72 None 158 

95 None 211 

120 None 263 

145 None 315 

2.3.1.2 Mechanical Ventilation to the 

Heated Space 

In the event that the heater(s) are to be 

9

installed without the positive connection of 

combustion ductwork within a heated space 

and where that heated space has a design 

air change of less than 0.5 air changes per 

hour and that the installer prefers to 

mechanically ventilate the heated space 

rather than provide ventilation openings then 

The heated space needs to be 

mechanically ventilated so that the 

design air change is 0.5 air changes 

per hour or greater. 

 

 

 

It is a requirement that the mechanical 

ventilation shall be of the !input! Type 

with either natural or mechanical 

extraction. 

Systems of mechanical extraction with 

a natural inlet shall not be used. 

It is necessary to provide an automatic 

means to safely inhibit heater(s) 

operation should mechanical air 

supply fail for any reason 

2.3.2 Heaters Installed within a Plant 

Room or Enclosure. 

A plant room means a room housing the 

heater plant and probably other items of 

building service plant and would generally 

have generous space for maintenance. 

An enclosure is where the heater is installed 

within a compartment or confined area 

where space is limited. 

Where heaters are installed within a plant 

room or enclosure then provision for both 

combustion air and / or air for general 

ventilation will be required by means of high 

and low level ventilation openings (sections 

2.3.2.1 and 2.3.2.2 refer to plant room 

applications and sections 2.3.2.3 and 

2.3.2.4 refer to enclosure applications). 

Alternatively the plant room or enclosure 

may be mechanically ventilated (section 

2.3.2.5 refers) 


to Plant Rooms for Room Sealed 

Heaters 

For plant room applications the minimum 

free area of ventilation opening will depend 

upon whether the heater(s) is installed in 

room sealed mode (ie with a positive 

connection to atmosphere of both flue and 

combustion air). 

Or with flue only (ie without the positive 

connection to atmosphere of a combustion 

air duct) 

Where the heater(s) is installed in a plant 

room and in room sealed mode (ie with a 

positive connection to atmosphere of both 

flue and combustion air ) the minimum free 

area of ventilation opening needs to be 

At high level 5 cm 2 for each kW of 

rated heat input. 

 

At low level 5 cm 2 for each kW of rated 

heat input 

The high level ventilation opening should be 

sited on an external wall and positioned as 

high as is practical and always within the top 

15% of the wall height. 




gas and ideally at floor level for l.p.g gas 


250 mm. 



MODEL 



High Level 

Low Level 

cm 2 cm 2 

30 160 160 

50 267 267 

72 394 394 

95 527 527 

120 656 656 

145 787 787 

10


to Plant Rooms for Flued Heaters 


room and in flue mode (ie without a positive 

connection to atmosphere of combustion air 

ductwork ) the minimum free area of 

ventilation opening needs to be 



 


heat input. 




15% of the wall height 






250 mm. 



MODEL 



High Level 

Low Level 

cm 2 cm 2 

30 64 128 

50 107 214 

72 158 316 

95 211 422 

120 263 525 

145 315 630 


to Enclosures for Room Sealed 

Heaters 

For enclosure applications the minimum free 

area of ventilation opening will also depend 

upon whether the heater(s) is installed in 

room sealed mode (ie with a positive 

connection to atmosphere of both flue and 

combustion air). 

11 

Or with flue only (ie without the positive 

connection to atmosphere of a combustion 

air duct) 


room and in room sealed mode (ie with a 

positive connection to atmosphere of both 

flue and combustion air ) the minimum free 

area of ventilation opening needs to be. 



 


heat input. 




15% of the wall height. 






250 mm. 



MODEL 



High Level 

Low Level 

cm 2 cm 2 

30 160 160 

50 267 267 

72 394 394 

95 527 527 

120 656 656 

145 787 787 


to Enclosures for Flued Heaters 

Where the heater(s) is in an enclosure and 

in flue only mode (ie without a positive 

connection to atmosphere of combustion air 

ductwork ) the minimum free area of 

ventilation opening needs to be:


rated heat input 

At low level 10 cm 2 for each kW of 

rated heat input 




15% of the wall height 

 

 

extraction rate should be 5%-10% less 

than the input rate. 

Systems of mechanical extraction with 

a natural inlet shall not be used 

It is necessary to provide an automatic 

means to safely inhibit heater(s) 

operation should mechanical air 

supply fail for any reason 






250 mm. 

The table that follows provides specific data 

for each heater model as - 

MODEL 



High Level 

Low Level 

cm 2 cm 2 

30 160 320 

50 267 533 

72 394 788 

95 527 1053 

120 656 1312 

145 787 1574 

The table that follows provides specific data 

for each heater model as - 

MODEL 

Mechanical Ventilation 

Rate for Plant Room or 

Enclosure 

M 3/ h 

30 133 

50 221 

72 327 

95 436 

120 543 

145 652 

2.3.2.5 Mechanical Ventilation to a 

Plant Room or Enclosure 

In the event that the installer prefers to 

mechanically ventilate the plant room or 

enclosure rather than provide ventilation 

openings then - 

 

 

The plant room or enclosure needs to 

be mechanically ventilated at the rate 

of 4.14 m 3 /h of fresh air per kW or 


It is a requirement that the mechanical 

ventilation shall be of the ’input’ type 

with either natural or mechanical 

extraction. Where mechanical 

extraction is selected then the 

12

2.4 Flue Installation. 

An integral flue spigot is fitted to all PV Air 

Heaters thereby allowing the flue to connect 

directly to the heater. 

The design of the flue must ensure that it 

can be disconnected to allow for cleaning 

and servicing. All joints should be sealed 

between the sections. 

Warning On PV72 to 145 a Combustion 

Air Plate is supplied as standard this 

MUST be fitted in place of the 

combustion air spigot if the heater is to 

be installed in the flue only option. 

It is essential that the products of 

combustion are flued to the outside of the 

building. 

Each heater must have its own separate 

flue, with a flue diameter of not less than is 

detailed in section 7.2 within this manual. 

The flue assembly must comply with all the 

relevant regulations regarding height and 

materials, and must terminate with an 

approved flue terminal. 

Care should be taken to ensure that the flue 

terminal is not situated in a high pressure 

area, the proximity of buildings and other 

obstacles which will influence this must be 

taken into account, preferably at the design 

stage. 

All PV Heaters are equipped with a built in 

flue venter fan which prevents the 

re circulation of combustion products, 

consequently an external draught diverter, 

barometric damper, or anti spillage system 

must not be installed. Such devices are 

unnecessary on the PV range of heaters. 

Horizontal flue installations must not 

exceed those stated in the following 

pages 

Each 90 0 bend corresponds to 1Mtr of flue 

length 

Each 45 0 bend corresponds to 0.8 Mtr of 

flue length 

In order to provide adequate natural 

draught, the minimum length of horizontal 

flue must not be less than 1m. 

For vertical flue installations the flue should 

rise vertically where possible bends should 

not exceed 45 0 and the number of bends 

should be kept to a minimum. 

Maximum vertical flue length must not 

exceed that stated in the following pages. 

The temperature of the combustion products 

can be as high as 170 0 C and therefore tend 

to rise naturally within the flue. Unnecessary 

bends and restrictions should therefore be 

avoided. 

Caution 

It is imperative that the flue should be 

properly sealed where it passes through the 

roof, this can best be achieved by using the 

approved method of roof flashing plate and 

cravat. The flue spigot outlet on all PV 

heaters is in vertical configuration. 

Note 

It should be noted that claims made under 

warranty and attributed to the ingress of 

water may not be considered especially if an 

approved method of sealing has not been 

used, or if the design of the flue has not 

made provision for possible condensation 

problems. 

It is also recommended that BS5854: 1980 

and BS5440: parts 1 and 2 are used as a 

consultative document when considering 

flue requirements. 

If terminating through a wall only use 

approved horizontal terminals 

Provision for the disconnection of the flue for 

servicing and inspection purposes must also 

be made. 

The position of the flue and its terminal 

should be such that it does not impair the 

combustion process. It should terminate in 

an exposed position so as to allow the free 

escape of flue gases without risk of their reentering 

the building through windows, 

ventilation ports etc. 

13

The following distances in mm’s should 

be observed 

200 below guttering or eaves 

the 25mm separation distance should be 

measured from the outside surface of the 

inner liner. 

300 from corners or openings (windows 

doors etc) and from other horizontal 

terminals on same wall 

1200 from a facing surface 

1500 from another terminal vertically on the 

same wall 

2000 from ground level 

The materials from which the flue is 

constructed must be non-combustible, 

resistant to internal and external corrosion, 

and be capable of withstanding the stresses 

and loadings associated with normal use. 

When designing the flue system the 

prevention of the formation and entrapment 

of condensation must be a key 

consideration. 

Horizontal flue should be fitted ensuring a 

slight gradient approx 2 0 towards the 

terminal Where condensation is unavoidable 

traps should be included to encourage the 

condensates to flow freely to a point from 

which they may be released, preferably into 

a gully. 

The condensate pipe from the flue to the 

disposal point must be made from corrosion 

resistant pipe of not less than 25mm internal 

diameter. 

If the flue passes through a wall, ceiling, or 

roof made from combustible material then it 

has to be sleeved so as to provide a 

minimum of a 25mm void between the 

exterior of the flue and the internal wall of 

the sleeve. 

For double wall flue pipe conforming to 

BS 4543-2 and 3 the external skin and air 

gap constitutes insulation to a standard 

where no extra clearance from combustible 

material is required other than normal 

installation tolerances 

Double walled pipe conforming to BS 715 

14

C 32 Vertical Co axial flue Kit Option 

In this configuration the heater is connected to a vertical flue system discharging the products of 

combustion and bringing in the combustion air from outside the building in which the heater is 

located. 

15

B 22 Single flue Option 

In this configuration the heater is connected to a single flue pipe to discharge the products 

of combustion outside the building either through the roof or through a wall. The air for 

combustion is taken from inside the building. 

Heater Unit Flue Exit HORIZONTAL Flue Exit VERTICAL 

MIN. MAX. COMBINED LENGTH MIN. MAX. COMBINED LENGTH 

30 m 1,00 6,00 1,00 10,00 

50 m 1,00 6,00 1,00 10,00 

72 m 1,00 8,00 1,00 10,00 

95 m 1,00 8,00 1,00 10,00 

120 m 1,00 8,00 1,00 10,00 

145 m 1,00 8,00 1,00 10,00 

16

Option C 12 

In this configuration the heater is connected to a horizontal flue system discharging the products of 

combustion and bringing in the combustion air from outside the building in which the heater is 

located. 

The outlet / inlet must be through the wall and may be made with a horizontal coaxial concentric 

terminal or two pipe 

17

2.5 Electrical Installation 

All electrical wiring and connections must be 

in accordance with the relevant European, 

National, and Local regulations as well as to 

IEE Standards. 

Benson PV Cabinets are available either for 

230/50/1ph or 415/50/3ph supply 

Warning 

Ensure that the electrical supply is 

compatible to the heater. 

ALL HEATERS ARE NEUTRALLY RESET 

Ensure that the Electric and Gas supplies 

are turned off before any electrical work is 

carried out on the heater. 

Also ensure that wiring cannot make contact 

with any metal surfaces liable to be subject 

to high temperatures, and where insulation 

of the wiring could be impaired as a result of 

such contact. 

All PV models must be earthed. 

Caution 

The main electrical supply must not be 

switched off or disconnected as a method 

for stopping the heater, the exception to this 

is in the event of an emergency, or when the 

heater has been allowed to cool sufficiently 

to prevent any damage from being 

sustained to the heater or its controls (ie: 

during servicing). Claims for damage will 

not be considered if they have resulted from 

incorrect wiring or the incorrect use of the 

heater. 

Each heater requires a permanent 230V 

50Hz 1ph or 415V 50Hz 3ph electrical 

supply, which must be wired through a fused 

isolator fitted with a fuse of the correct rating 

(see section 7.1). The correct supply 

connection points for the live, neutral, and 

earth. 

Wiring diagrams are also detailed within this 

manual, (section 6.0 ). 

The electrical supply isolator should be 

mounted adjacent to the air heater in an 

easily accessible position to allow for 

servicing isolation, or emergency shut off. 

Electrical panel 

Warning 

Ensure that the mains isolator is turned OFF 

before undertaking any electrical work on 

the heater. 

Access to the electrical panel is gained by 

opening the front panel. 

Warning 

Ensure that all connections are secure and 

that there are no loose strands which could 

bridge across the terminals. 

A minimum conductor size of 1.0 mm 

(diameter) is required. 

Remote Control Panels 

Warning 

Isolate panel before working on 

heater 

One electrical panel per heater is required, 

unless heaters are specified for multiple 

heater control applications. On no account 

should more than one heater be connected 

to a single time switch or thermostat. 

The only exception to this is when a control 

panel suitable for multiple heater 

applications is supplied by the manufacturer. 

Any ancillary electrical items e.g. room 

thermostats , time switches, remote panels 

etc, must be wired into the heater electrical 

circuit in accordance with the diagrams 

provided 

Note 

When external controls operate to switch the 

heater OFF, power to the heater should 

remain to allow the fan to continue to 

operate to sufficiently cool the heater 

thereby preventing damage to the heat 

exchanger. 

Fan limit control 

( Situated inside the front panel) 

These settings may require slight 

adjustment on commissioning. 

Fan control (white button) FAN ON 50°C 

FAN OFF 30°C 

18

The fan control switch features normally 

open 230V contacts, and is wired to control 

the live supply to the fan motor . When the 

circuit is made, the fan will switch on when 

the heat anticipator has closed the fan 

switch contacts. When the thermostat or 

time switch shuts down the burner, the fan 

will continue to run until the thermal switch 

has cooled sufficiently to prevent the 

residual heat from damaging the heater or 

its controls. 

On start up the fan delay prevents air being 

circulated until the desired temperature is 

achieved 

Limit control (red button) SET at 100 c 

An adjustable high temperature manual 

reset limit control. If this control needs 

resetting the cause should be determined 

and rectified immediately. 

Caution 

The power supply to the fan must not be 

interrupted, the only time when power 

supply can be disconnected or interrupted is 

during servicing or in emergencies. 

If there is a requirement for the heater to be 

switched off over night then the gas valve 

circuit should be opened via a time switch, 

etc, as per the wiring instructions and 

diagrams supplied within section 6.0 of this 

manual. 

19

2.6 Gas installation 

Warning 

Please read notice on page 3 of this 

manual 

As there have been recorded instances of 

the deposition of copper sulphide dust within 

the valves and orifices of gas appliances as 

a direct result of a reaction between the 

hydrogen sulphide contained in some 

natural gasses and copper pipe we 

recommend that the heater(s) should not be 

connected to any natural gas pipe 

distribution system which utilizes copper 

pipework, including final connections. 

Instead steel pipework should be used 

throughout. 

In the event that it is impractical to use steel 

pipework or where installers are obliged or 

insist on using elements of copper pipework 

within the installation then we strongly 

recommend that the gas supplier be 

consulted as specific conditions and 

requirements may be necessary. 

The PV Range of heaters are all 

manufactured and pre set for use with 

Natural Gas, and all feature 1/2” or 3/4” BSP 

connection points. Prior to installation the 

supply characteristics (gas type and 

pressure) must be checked to ensure that 

they are in accordance with the data plate 

on the heater. 

The gas supplier should check that the 

meter and service connection to the heater 

are capable of delivering the required 

volume of gas, thereby ensuring that the 

minimum burner pressure can be achieved. 

Each heater supply must be fitted with a 

separate isolating cock positioned adjacent 

to and upstream of the union which must be 

sited outside the heater. 

The isolating cock should be of the 90 0 turn 

type and should be clearly marked OPEN / 

CLOSED it should also be installed so as to 

fall to the closed position. 

An approved gas jointing compound must 

be used on all joints and unions and the 

system purged and tested for soundness 

prior to final connection. 

The connection to the heater can be made 

by way of either an approved flexible 

coupling or rigid connection . Threaded 

connections must comply to ISO 288/1 or 

ISO 7/1 further information concerning 

accepted European practice is detailed in 

BS EN1020 1998. 

The diameter of the pipework from the 

isolating cock to the burner must not be less 

than the diameter of the connection into the 

multiblock. 

Note 

Reference to The Institute of Gas Engineers 

publications Utilisation Procedures IGE/UP1 

and IGE/UP2 together with reference to 

BS6891 is strongly advised. 

Nozzle Hoods 

Ensure nozzle hoods are pointing in the 

correct direction and are secured to top 

plate by drilling through the holes provided 

in the hood ring and securing with self 

tapping screws. 

Consideration should be given to the 

pressure drop on single and multi heater 

installations and the effect they may have on 

other plant sharing the supply. 

If it is necessary to fit a gas pressure 

booster, the controls must include a low 

pressure cut off switch which must be fitted 

on the supply / inlet side of the booster. It is 

also a requirement that the gas supplier is 

advised prior to the installation or fitting of 

the booster. 

20

3.0 Commissioning 

Note 

It is a requirement that only suitably 

qualified and competent personnel are 

allowed to undertake the commissioning 

of the heater. 

It is also strongly recommended that prior 

to commissioning the engineers 

familiarise themselves with the heater. the 

specific requirements of the installation / 

application, and the information 

contained within the manual. 

Warning 

All heaters are subject to a rigorous test 

programme prior to despatch, whilst such a 

programme does involve pre-commissioning 

and the setting of the heater to operate 

efficiently and within its designed operational 

limits this does not mean that the function of 

thorough on site commissioning is less 

important 

It is strongly recommended that the 

equipment used for the sampling and 

analysis of the flue gases is accurate to 

within +/- 0.1% and maintained so that it is 

regularly calibrated. 

The following pre-commissioning checks 

should be undertaken, having first ensured 

that the gas and electrical supplies are 

turned off. 

(a) Check that all panels and fasteners are 

secure and in place. 

(b) Check that the heater is installed safely. 

(c) Check that the flue is sealed, secured, 

and adequately supported. 

(d) Check that the fan is free to rotate, that 

the fan is secured to its shaft, and that the 

guards and fan assembly are all in place and 

properly secured. 

(e) Check that the heater is installed so that 

it is not tilted and remains square. 

(f) Check that the outlet louvres are set to 

offer minimum resistance to air flow. 

3.1 Electrical pre-tests 

The electrical safety checks must include the 

following: 

a) Test for earth continuity 

b) Test for resistance to earth 

c) Check live and neutral connections are 

correct. 

d) Check to ensure that when the external 

controls operate to switch the heater off, 

power remains to the fan 

3.2 Gas supply pre-test 

Ensure that the service pipework has been 

installed purged and tested in accordance 

with the relevant regulations, and that the 

installation is served by an adjacent isolating 

cock. 

Connection from the supply to the heater 

must also comply with the relevant 

regulations (see section 8.0) and must have 

been purged and soundness tested by an 

authorised engineer 

3.3 Ignition sequence 

PRE START DRY RUN 

In order to test that all controls are in good 

working order, the control sequence should 

first be tested with the gas supply turned Off. 

Ensure gas isolating cock is in the Off 

position 

Warning 

If during the following sequence of 

operations the heater fails to operate 

correctly the fault should be traced and 

rectified before proceeding, if necessary 

referring to section 5.0 fault diagnosis. 

a) Switch off the main electrical supply to the 

heater. 

b) Turn off gas supply to the heater. 

c) Open side panel, and connect 

manometers to the gas supply test point and 

to the main burner test point. 

d) Ensure outlet louvres are correctly set. 

e) Ensure fan rotation is not impaired or 

obstructed. 

f) Set room thermostat to its lowest setting. 

g) If a time switch is fitted ensure it is set to 

an ON period. 

h) Switch on electrical supply. 

i) Use leak tester to test for soundness on 

the unions and pipework. 

j) Operate the heater through the installed 

control system. 

21

On start the signal will activate the flue 

venter for a pre purge period and in turn will 

make the air proving switch, once made, the 

air proving switch will complete the circuit to 

the control box and after a 40 second Delay 

the automatic control should attempt light 

the burner, because the gas is turned off 

and flame cannot be established , the 

control box will go to LOCKOUT. 

k) Reset the control on completion of dry 

run. 

l) Open gas cock. 

m) Operate heater through installed control. 

The flue venter will pre purge the heater and 

in turn operate an air proving switch which 

completes the electrical circuit to the control 

box after a 40 second Delay the control will 

open the gas solenoid valve and the main 

burner will light. 

The flame can be observed at the burner 

manifold, check that the burner is providing 

a good flame i.e. even and stable. 

n) Check pressure readings on the 

manometers, and continue to let the heater 

fire for ten minutes. 

o) When the fan starts ensure that the 

direction of rotation is correct , and that the 

fan start is within 2 minutes of burner 

ignition. 

Caution 

If the fan fails to operate within 

approximately 2 minutes and the heater 

goes to overheat it will shut down through 

breaking the circuit to the gas valve, the 

cause must be ascertained and rectified 

before re-ignition. 

Once the limit thermostat has tripped out it 

must be manually reset to allow re-ignition 

to take place. 

p) After ten minutes check burner head 

pressure is as specification - adjust as 

necessary by removal of the gas pressure 

adjustment cover, and using a screwdriver 

turn the adjustment screw on the governor 

as follows: Clockwise to increase. Anti 

clockwise to decrease. 

q) Check that the gas pressure remains 

satisfactory for all appliances on the same 

circuit. 

r) Undertake combustion tests checking CO 

CO 2 and efficiency (see section 7.0) CO 

should not exceed (20PPM). 

s) Check that the burners are extinguished 

when the thermostat is set to its lowest 

setting, and then remove the manometers. 

t) Turn the thermostat to its highest setting 

to re light the burner and replace the 

adjustment screw cover. 

On completion mark the gas valve 

adjustment screw with paint/sealant to 

prevent tampering with valve 

u) Turn the thermostat to its lowest setting 

and shut off the gas supply at the gas 

control valve, allow the fan to continue to 

run until the heater is cooled sufficiently for 

the fan to shut down. 

v) Turn off the electrical supply. 

w) Close the side panel. 

x) Set thermostat to desired setting. 

y) Ensure that the user is familiar with the 

heater and its controls and that the user is 

satisfied with the commissioning and 

testing, and that he is aware of the 

instructions within the manual. 

It is strongly advised that the commissioning 

engineer runs through the lighting, 

shutdown, and general safe and efficient 

running of the heater before hand over. 

On Completion of commissioning the fan 

belts should checked for the correct 

tension 

3.4 Hand over 

Upon satisfactory completion of 

commissioning and testing, a record of 

commissioning information (contact name 

date etc) should be made in the log book left 

with the heater by the commissioning 

engineer together with the user instructions. 

At the same time the user should be made 

aware of the most efficient and economical 

methods of operation. 

The user must be familiar and satisfied with 

the safety, ignition, shutdown, and general 

operational procedures. 

22

4.0 Servicing 

Warning 

It is a requirement that only qualified 

personnel are allowed to carry out 

installation commissioning or servicing. 

In addition only spare parts recommended 

by the manufacturer may be fitted, and the 

installer should provide a list of 

recommended spare parts that are available 

through the manufacturer or his agent (see 

section 8). 

Before commencing any maintenance or 

servicing work the heater must be shut 

down and allowed to cool, and have the gas 

and electric supplies to it turned off at the 

supply cock and isolator respectively. 

Always test for gas soundness after 

completing any service work particularly 

if this has necessitated the removal and / 

or replacement of gas carrying 

components. 

It is advisable that routine inspections are 

carried out on a frequent basis, servicing 

must also be carried out regularly, and in 

accordance with the manufacturers 

recommendations i.e. at a maximum interval 

of one year. In certain applications the 

frequency of servicing will have to be 

increased, this to a large extent is governed 

by the working environment, and both the 

manufacturer and the installer will be able to 

offer further advice. 

Clean all accessible surfaces including the 

outside of the tubular heat exchanger by 

removal of the rear panel. 

Check for panel damage and that all 

fasteners are present and secure. 

Visually check all electrical wiring for signs 

of damage, possibly through contact with 

hot surfaces, check conduit for signs of 

chaffing and for security . Check all 

terminals are secure and free from 

escaped / stray conductor strands. 

4.1 Servicing procedure - major 

component parts 

Heat exchanger 

Remove rear panel and carry out visual 

inspection of the tubular heat exchanger 

using an inspection lamp and mirror. 

Check seams and joints for perforations. 

Check for severe corrosion and splits in the 

heat exchanger. 

Check that there are no blockages and that 

there is not an excessive build up of soot 

within the heat exchanger tubes. 

If required remove the burner manifold 

allowing access for cleaning, with a flexible 

flue brush and vacuum cleaner. 

Warning If the heat exchanger is found to 

be perforated the heater must not be fired 

until a replacement heat exchanger has 

been fitted 

Injectors and Manifold 

Undo the gas pipe connection. 

Remove the manifold fixing screws. 

Remove the manifold and injector assembly 

from the right hand side of the heater. 

Check that the manifold is straight, the 

injectors are correctly aligned, and that they 

are clean, and that there are no 

contaminates restricting the orifices, if 

necessary clean carefully with compressed 

air and or lint free cloth and acetone. 

Caution 

The injector orifice is precision machined to 

fine tolerances, do not clean with hard sharp 

or abrasive instruments. If the injectors have 

been removed from the manifold, when they 

are replaced, and care should be taken not 

to over tighten. 

Ensure all joints are gas tight. 

Fan and Limit Thermostats 

Open the front door, so as to gain access. 

Remove securing screw from cover, remove 

23

cover plate and disconnect the cables. 

Remove the screws which secure the unit to 

the side of the heater and withdraw the 

thermostat complete from the heater. 

Check that the bi metal coil and its housing 

are secure clean as necessary with a soft 

brush. 

Flue System 

Check that the flue is in good condition, that 

it is adequately supported, that there are no 

blockages or restrictions. 

Check that any joints are properly sealed 

preventing an escape of products of 

combustion. 

Check condensate drain if fitted . 

Check for signs of water ingress and any 

resultant damage. 

Flue Venter 

Check that the flue fan is clean and free 

from any dust deposits 

Differential Air Pressure Switch 

Check that the tubes are connected and 

clear and free from dust. 

Check that they are not kinked or damaged. 

Check electrical connections are intact. 

Fan and Motor complete 

Check that the fan is secure and rotates 

freely without excessive play in the shaft. 

The fan blades and motor should be 

cleaned using a soft brush. 

Check that the bearings do not show signs 

of excessive wear. 

It should be noted that these bearings do 

not require lubricating. 

Main Fan Motor 

Remove access panel. Dust and other 

foreign matter should be cleaned by blowing 

over with compressed air and through the 

use of a soft bristle brush and cloth. Solvent 

wipes may be used to remove heavy soiling 

from the motor casing. 

The electrical connections should be 

checked as follows. 

The cover to the terminal box should be 

removed by undoing the screws, which 

secure it. 

Check connections for signs of corrosion, 

tightness, and ensure that there are no stray 

strands which could form a short circuit. 

Clean, tighten, and replace as necessary. 

Replace cover and secure. 

Main Fan 

Remove dust and other foreign matter by 

blowing off with compressed air or through 

the use of a soft bristle brush. Check that 

the bearings do not show signs of excessive 

wear. 

It should be noted that these are sealed 

bearings if they are worn the whole fan 

assembly will require replacement the 

following procedure should be carried out. 

(a) Release the tension on the belt(s) and 

remove. 

(b) Unbolt and remove fan from heater 

(c) Remove taperlock and pulley 

(d) Fit taperlock and pulley to new fan 

(e) Refit fan into heater and bolt in place . 

(f) Refit the belts. 

(g) Turn by hand to ensure free fan rotation. 

Pulleys 

Check pulleys for alignment using a straight 

edge, if necessary reposition either or both 

of the pulleys and the fan motor. 

Check for excessive wear within the root 

and sides of the grooves, and check for any 

other signs of wear or damage, if necessary 

replace the pulley as follows. 

(a) Release tension on belts and remove. 

(b) Release the taper locks by slackening 

the securing screws by several complete 

turns. 

24

(c) Fully remove one screw from the taper 

lock, and having oiled it, insert into the 

threaded jacking point. 

(d) Tighten screw until the taperlock is free. 

(e) Remove taperlock and pulley. 

(f) Fit taperlock in new pulley, and 

provisionally position on the shaft. 

(g) Remove the screw from the jacking 

point, and tighten both screws in their 

clamping points until the pulley can just be 

moved on the shaft by hand. 

(h) Align pulleys using a straight edge, and 

by gradual alternate tightening of the screws 

clamp in position. 

(i) Refit belts and check for the correct 

amount of tension. 

Fan Belts 

Check belts for signs of wear. Frayed or split 

belts must be replaced using belts with a 

common batch code. Belt tension must be 

checked, and if on multi-belt units it is found 

that one belt contains more slack than its 

accompanying belts, then all the belts on the 

unit must be replaced, again using a 

common batch code. Replacement and 

tensioning is carried out as follows. 

Note 

The maximum displacement at the mid point 

of the top edge of the belt must not be 

greater than 16mm per metre of span, when 

a force of 3kg is applied in a plane 

perpendicular to the belt. 

(a) Loosen fan motor securing bolts on 

chassis. 

(b) Loosen fan motor slide adjustment bolt. 

(c) Slide motor towards fan to slacken belts. 

(d) Replace belts, pull fan motor away from 

fan until belts are tight. 

(e) Tighten adjustment bolt to hold motor. 

(f) Tighten fan securing bolts ensuring that 

the fan is square and the pulleys aligned. 

(g) Check belt tension, making final 

adjustments as necessary. 

(h) Tighten and clamp fasteners to hold fan 

motor in position. 

Automatic Controls 

Automatic control is by way of a Honeywell 

controller. 

Spark Ignition is via an ignition electrode 

Ensure that the ceramic insulation material 

is not damaged or cracked. 

Flame supervision is via a flame sensor rod. 

Check the flame sensor rod for signs of 

pitting or corrosion, ensure that the ceramic 

insulation material is not damaged or 

cracked. Check connections are secure. 

Main Governor 

To adjust the main governor, using a 

screwdriver remove the metal cover to 

reveal the adjustment screw, and turn as 

follows : 

Clockwise to increase pressure. 

Anticlockwise to decrease pressure. 

It should be noted that full clockwise 

adjustment will result in the valve being 

closed permanently. 

Gas Supply 

The gas supply pipe work and fittings should 

be inspected to ensure they are free from 

corrosion and that where brackets have 

been fitted these remain secure and offer 

adequate support. The system should be 

soundness tested in accordance with 

Institute of Gas Engineers recommendations 

detailed in Utilization Procedures IGE/ UP-1 

and 2 

Test 

Test and re-commission as per sections 3.0 

to 3.4 inclusive 

Report 

A full and detailed service report should be 

prepared, it is advised that the report is not 

completed until the heater has been recommissioned, 

where upon the completed 

report can then be run through with the user. 

This must be regarded as a necessary part 

of the heater service by the servicing 

engineer. 

25

5.0 Fault finding 

Burner 

fails to 

light 

Electric 

Supply ON 

No 

Turn on Electric 

Supply 

Yes 

Check fuse Replace if 

required 

Yes 

Flue fan running 

No 

Check flue fan 

connections 

Yes 

Replace flue fan 

Yes 

Air pressure 

switch made 

No 

Check flue is clear 

Yes 

Change air 

pressure switch 

d 

Yes 

Thermostat 

calling for 

heat 

Yes 

Limit thermostat 

operated 

Yes 

Reset Limit 

thermostat 

Yes 

Gas Supply 

ON 

No 

Turn on Gas 

Supply 

Yes 

Air in Gas 

Supply 

Yes 

Purge Gas Line 

No 

Spark ignition 

on 

No 

Check HT leads 

and 

connections 

Yes 

Faulty control 

box 

Yes 

No flame 

Yes 

Faulty Gas 

valve 

Yes 

Change gas 

valve 

26

Fault finding cont’d 

Fan will 

not run 

heater 

goes off 

on limit 

Yes 

Bad 

electrical 

connection 

No 

Yes 

Check 

wiring 

connection 

Fan control 

settings 

incorrect 

Yes 

Reset fan 

control 

settings 

No 

Fan runs in 

manual 

mode 

Yes 

Faulty fan 

control 

Yes 

Change fan 

control 

No 

Faulty fan 

motor or 

capacitor 

Yes 

Change fan 

motor or 

capacitor 

Check air 

inlet / 

discharge not 

restricted 

Yes 

Remove 

obstruction 

clean filters 

Yes 

Burner 

starts but 

heater 

goes to 

overheat 

Yes 

Insufficient 

airflow over 

heat 

exchanger 

Yes 

Fan belts 

slipping 

/impellor 

loose on 

shaft 

No 

Adjust /replace 

belts tighten 

impellor 

or 

Faulty fan / 

limit stat 

Yes 

Change fan / 

limit stat 

or 

High return 

air 

temperature 

Yes 

Check for warm air 

short circuit wiring to 

air inlet 

27

Wiring Diagram 33-66-496 

PV 30-50 ON/OFF Auto Ignition 

SC³-SZ 230/50/1ph (SmartCom Integral Controller) 

T 

T 

28




T 

T 

29




T 

T 

30



SC³-SZ 230/50/1ph (Remote SmartCom Controller) 

T 

T 

31




T 

T 

32




T 

T 

33



CP4 230/50/1ph (Integral CP4 Controller) 

T 

T 

34




T 

T 

35




T 

T 

36



Less Controls 230/50/1ph (No Controller) 

T 

T 

37




T 

T 

38




T 

T 

39


PV 30-50 HI/LOW Auto Ignition 

SC³-MZ 230/50/1ph (Remote SmartCom Controller) 

T 

T 

40




T 

T 

41




T 

T 

42

7.0 Technical Data 

Appliance Type B 22 C 32 C 12 

Electrical Protection 

IP20 

7.1 Technical Data Common Information 

Country 

AT,CH,CZ,DK,EE,ES,FI,GB,GR,HU,IE,IT 

IS,LT,LV,NO,PT,RO,SE,SI,SK,TR 

BE,CZ,NL,FR,DE,IE,IT,ES,CH,PT,GB,SE, 

SK,SL,PT,PL,TR 

PL,LU,DE,RO 

PL 

PL 

Approved Gas Category 

I 2H 

I 3P 

I 2E 

I 2LS 

I 2LW 

43

7.2 Technical Data - Heater Specifications 

NAT GAS / LPG MODEL 30 50 72 95 120 145 

HEAT 

OUTPUT 

kW 

Btu 

29.4 

100,000 

49.0 

167,000 

72.0 

246,000 

96.0 

328,000 

120.0 

409,000 

144.0 

491,000 

HEAT 

INPUT (Nett ) 

kW 

Btu 

32.0 

109,180 

53.3 

181,700 

78.8 

268,900 

105.2 

359,000 

130.4 

445,000 

156.5 

534,000 

EFFICIENCY % Nett 92.0 92.0 91.4 91.2 91.5 91.5 

EFFICIENCY % Gross 82.8 82.8 82.3 82.1 82.4 82.4 

HEAT 

OUTPUT Low Fire 

kW 

Btu 

14.2 

48,400 

23.6 

80,800 

34.9 

119,100 

46.6 

158,900 

57.7 

197,000 

69.3 

236,500 

HEAT 

INPUT (Nett ) Low Fire 

kW 

Btu 

16.0 

54,600 

26.7 

91,200 

39.4 

134,500 

52.6 

179,500 

65.2 

222,500 

78.3 

267,200 

GAS CONNECTION BSP/Rc 1/2” 1/2” 3/4” 3/4” 3/4” 3/4” 

MIN INLET 

PRESS NAT GAS 

mbar 

Ins WG 

17.5 

7.0 

17.5 

7.0 

17.5 

7.0 

17.5 

7.0 

17.5 

7.0 

17.5 

7.0 

BURNER 

PRESSURE NAT GAS 

mbar 

Ins WG 

8.3 

3.3 

8.3 

3.3 

6.8 

2.7 

7.0 

2.8 

9.2 

3.7 

9.2 

3.7 

BURNER PRESSURE NAT 

GAS HI LO 

Hi mbar 

Lo mbar 

8.3 

3.3 

8.3 

3.3 

6.8 

2.5 

7.0 

2.6 

9.2 

3.8 

9.2 

3.8 

MAIN INJECTOR 

NATURAL GAS 

mm 

No Off 

2.2 

6 

2.2 

10 

3.0 

9 

3.0 

12 

3.4 

10 

3.4 

12 

NAT GAS 

CONSUMPTION 

ft 3 /hr 

m 3 /hr 

119 

3.38 

199 

5.63 

294 

8.33 

393 

11.12 

490 

13.87 

587 

16.63 

MIN INLET 

PRESS LPG 

mbar 

Ins WG 

37.0 

14.8 

37.0 

14.8 

37.0 

14.8 

37.0 

14.8 

37.0 

14.8 

37.0 

14.8 

BURNER 

PRESSURE LPG 

mbar 

Ins WG 

29.2 

11.68 

29.2 

11.68 

28.7 

11.5 

28.7 

11.5 

25.5 

10.2 

25.5 

10.2 

LPG PROPANE 

CONSUMPTION 

m 3 /hr 

Kg/h 

1.30 

2.41 

2.16 

4.00 

3.21 

5.94 

4.28 

7.92 

5.34 

9.88 

6.41 

11.86 

MAIN INJECTOR 

PROPANE 

mm 

No Off 

1.3 

6 

1.3 

10 

1.6 

9 

1.6 

12 

2.0 

10 

2.0 

12 

TEMPERATURE 

RISE 

ºC 

ºF 

30 

54 

37 

67 

39 

70 

34 

61 

32 

58 

32 

58 

AIR 

FLOW 

ft 3 /min 

m 3 /sec 

1695 

0.80 

2225 

1.05 

3179 

1.50 

4874 

2.30 

6463 

3.05 

7756 

3.66 

CENTRIFUGAL FAN STATIC 

PRESSURE 

Pa 

Ins WG 

80 

0.32 

SOUND LEVEL @ 3m Dba 63 64 72 74 74 76 

110 

0.44 

FLUE DIAMETER mm 100 100 130 130 130 130 

COMBUSTION AIR DIA mm 100 100 130 130 130 130 

SUPPLY VOLTAGE Standard 230/1/50 230/1/50 230/1/50 415/3/50 415/3/50 415/3/50 

ELECTRICAL POWER Amps 3.2 3.2 7.2 3.6 5.2 6.5 

INTERNAL FUSE RATING Amps 10 10 10 6 6 6 

POWER ABSORPTION kW 0.4 0.4 1.2 1.6 2.3 3.1 

FUSED ISOLATOR SIZE Amps 16 16 20 16 16 25 

GROSS FLUE TEMP ºC 145 150 150 150 160 160 

Nett WEIGHT Kgs 192 202 330 380 440 460 

AIR PRESS SWITCH mbar 1.03 1.03 1.65 1.65 1.65 1.65 

100 

0.40 

130 

0.50 

150 

0.60 

150 

0.60 

FLUE 

RESISTANCE 

min mbar 

max mbar 

-0.1 

+0.2 

-0.1 

+0.2 

-0.1 

+0.2 

-0.1 

+0.2 

-0.1 

+0.2 

-0.1 

+0.2 

44

8.0 Parts List 

MODEL 30 50 72 95 120 145 

Fan Motor Assy 28-09-001 28-09-001 28-09-002 N/A N/A N/A 

Fan Centrifugal / 1ph 

Fan Centrifugal / 3ph 

Fan Motor / 1ph 

Fan Motor / 3ph 

Fan Pulley 

Taper Lock 

Motor Pulley / 1ph 

Motor Pulley / 3ph 

N/A 

N/A 

N/A 

N/A 

N/A 

N/A 

N/A 

N/A 

N/A 

N/A 28-09-003 28-09-149 28-09-149 

N/A 

N/A 

N/A N/A N/A 

N/A N/A N/A 

Motor Taper Lock N/A N/A N/A 

28-10-117 

28-10-127 

28-65-105 

28-66-136 

28-65-072 

28-65-072 

28-66-124 

28-66-124 

28-10-117 

28-10-127 28-10-015 

28-65-105 

28-66-136 

28-65-105 

28-66-136 

28-65-078 

28-65-078 28-65-079 

28-66-124 

28-66-124 28-66-028 

Belts x 2 N/A N/A N/A 09-16-126 09-16-093 09-16-093 

Fan Limit Stat 28-60-023 28-60-023 28-60-023 28-60-021 28-60-021 28-60-021 

Gas Valve 28-30-180 28-30-180 28-30-181 28-30-181 28-30-184 28-30-184 

Control Box 29-01-173 29-01-173 29-01-183 29-01-183 29-01-183 29-01-183 

Injector Natural Gas 33-64-144 33-64-144 33-66-011 33-66-011 33-64-145 33-64-145 

Injector LPG Propane 33-67-322 33-67-322 33-66-014 33-66-014 33-64-147 33-64-147 

Air Pressure Switch 33-62-119 33-62-119 28-40-139 28-40-139 28-40-139 28-40-139 

Flue Fan 28-09-083 28-09-084 28-09-089 28-09-089 28-09-090 28-09-090 

Electrode 33-64-193 33-64-193 33-64-193 33-64-193 33-64-193 33-64-193 

Ionisation Probe 33-64-194 33-64-194 33-64-194 33-64-194 33-64-194 33-64-194 

MCB 28-07-085 28-07-085 28-07-084 28-07-084 28-07-084 28-07-084 

Overload 1ph 

Overload 3ph 

N/A 

N/A 

28-11-028 

N/A 

28-11-130 

28-11-026 

28-11-130 

28-11-126 

N/A 

28-11-127 

Contactor N/A N/A 28-11-131 28-11-131 28-11-131 28-11-131 

Rocker Switch Red Neon 28-40-105 28-40-105 28-40-105 28-40-105 28-40-105 28-40-105 

Rocker Switch Dual 28-40-106 28-40-106 28-40-106 28-40-106 28-40-106 28-40-106 

Room Thermostat 28-16-031 28-16-031 28-16-031 28-16-031 28-16-031 28-16-031 

Frost Thermostat 28-16-044 28-16-044 28-16-044 28-16-044 28-16-044 28-16-044 

Time Clock (Digital) 28-15-030 28-15-030 28-15-030 28-15-030 28-15-030 28-15-030 

45

WARNING 

9.0 Heater Dimensions 

MODEL A B C D E F G H I J K L M N P 

30 1650 700 1080 100 189 263 1725 570 25 570 103 967 280 285 N/A 

50 1650 700 1080 100 189 263 1725 570 25 570 103 840 280 324 N/A 

72 1830 840 1395 130 255 311 1890 769 40 984 169 963 314 352 677 

95 1830 840 1395 130 255 311 1890 769 40 984 169 894 314 352 677 

120 1960 840 1625 130 255 283 2020 769 40 1214 95 934 355 410 815 

145 1960 840 1625 130 260 287 2020 769 40 1214 95 894 355 410 815 

46

Dimensions - Flue 

994mm 

494mm 

244mm 

100mm Stainless Steel Flue Fittings. 

For heater size PV30 - PV50 

Ø100.75mm 

119mm 

220mm 

111mm 

Pipe 1m Long 

161mm 

233mm 

169mm 

Ø99.8mm 

224mm 

164mm 

211mm 

Elbow 45° 

Elbow 90° 

775mm 

220mm 

Ø149mm 

140mm 

Pipe 0.5m Long 

1361mm 

Ø149.3mm 


220mm 

253mm 

859mm 

249mm 

170mm 

370mm MAX 

Horizontal Concentric Terminal 

140mm 

Vertical Concentric Terminal 

994mm 

494mm 

244mm 

130mm Stainless Steel Flue Fittings. 

For heater size PV72 - PV145 

Ø130.75mm 

124mm 

300mm 

116mm 

Pipe 1m Long 

173mm 

252mm 

181mm 

Ø129.8mm 

251mm 

193mm 

238mm 

Elbow 45° 

Elbow 90° 

840mm 

300mm 

Ø200mm 

227mm 


1895mm 

Ø200mm 


300mm 

355mm 

1285mm 

255mm 

180mm 

385mm MAX 

Horizontal Concentric Terminal 

227mm 

Vertical Concentric Terminal 

47

Document reference number 33-66-161 Nov 2011 Issue 14 

Technical Support: 

Tel: 01384 489 200 

Fax: 01384 489 707 

ambiradgroupsupport@tnb.com 

www.ambiradgroup.co.uk 

48

INSTALLATION & SERVICING MANUAL BENSON PV TUBULAR CABINET HEATER

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